The prior art is replete with apparatus for driving wheel chairs and bicycles. Examples of such apparatus found in a search of prior art for such apparatus are disclosed in U.S. Pat. Nos. 4,865,344; 4,762,332; 4,652,026; 4,453,729; 4,274,651; 4,063,747; 3,994,509; 3,877,725; 3,666,292; 3,309,110; 1,273,693 and 494,839.
A review of the above patents reveals that none of the apparatus disclosed therein is capable of receiving or transmitting linearly generated power, i.e. power which is generated by power strokes traveling along a straight line or path. All apparatus disclosed in the patents require that the operator move a handle or pedal through some sort of an arcuate or curved path in order to make a power stroke with a device. For example, in U.S. Pat. No. 3,877,725 to Barroza, it can be seen in FIG. 4 that the wheelchair is driven by moving handle 3 through the arcuate path illustrated by the arrows in FIG. 4. Similarly, in U.S. Pat. No. 4,063,747 to Young, it can be seen in FIG. 1 that the bicycle disclosed therein is powered by moving pedals 36 through an arcuate path. It will also be appreciated that the pedal of a conventional bicycle also follows an arcuate path as it revolves about the axis of the bicycle's main sprocket.
One problem with generating power along a curved or arcuate path is that the portion of the path over which maximum power can be generated is very short. For example, in a conventional bicycle, maximum power is generated during that portion of the pedal's path which travels from about +45.degree. from the horizontal to about -30.degree. from the horizontal. As can be visualized, it is difficult to generate significant power outside this portion of the pedal's path since the operator's foot is simply not at an angle with respect to the pedal which enables the generation of much power.